The disclosure relates, in general, to a display device, a backlight module and a method of fixing a circuit board on such a backlight module, and more particularly, to a display device using a side type backlight module and a method of fixing a circuit board on such a backlight module.
Along with the rapid advance in the technology of manufacturing flat display panels, which possess various advantages, such as lightweight, small volume, low power consumption and low or zero radiation, flat display panels have now been widely used in various electronic products such as personal digital assistants (PDA), notebook computers, digital cameras, mobile phones, computer screens and flat TVs. As the industry puts emphasis on research and development and adopts large-scale production, the quality of flat display panels has been improved and the price keeps dropping, and the area of application is rapidly expanded.
Generally speaking, a display device using a flat display panel has a circuit board, which is connected to the display panel and/or other external circuits via a cable. According to a method known to the inventor(s) for fixing the circuit board, the circuit board is fixed on a plastic housing by screws or adhesive, and the backlight module and the display panel are disposed in a front iron frame. To further reduce the thickness of the backlight module of the display device, the plastic housing only surrounds the backlight module so that the circuit board is directly located on the reflector. FIG. 1A shows a schematic, perspective view of a display device known to the inventor(s), and FIG. 1B shows a cross-sectional view of the display device of FIG. 1A taken along a cross-sectional line A-A′. The display device 10 includes a front iron frame F, a display panel 11 and a backlight module 12. The display panel 11 is disposed at one side of the backlight module 12. The display panel 11 and the backlight module 12 are contained in the front iron frame F. The backlight module 12 includes a plastic housing 19, a lamp cover 13, a circuit board 14, a reflector 17, a light guide plate 16, a light source 15 and multi-layered optical sheets 18. The reflector 17 is disposed at one side of the light guide plate 16. The multi-layered optical sheets 18 are disposed at the other side of the light guide plate 16 and opposite to the reflector 17. The lamp cover 13 is adjacent to the light guide plate 16, and located at one side of the light guide plate 16 for containing the light source 15, and receiving a part of the reflector 17 and the light guide plate 16. The circuit board 14 is disposed at the side of the light guide plate 16 opposite to the display panel 11, and is connected to the display panel 11 through the flexible circuit board C. The plastic housing 19 surrounds the reflector 17 and the light guide plate 16 so as to further reduce the thickness of the backlight module 12. As the circuit board 14 is directly located on the reflector 17, the circuit board 14 can only be fastened, e.g., by screws, on the plastic housing 19 from the two sides. When the cable P is plugged into a connector 14a of the circuit board 14 or unplugged from the connector 14a, the circuit board 14 may move relatively to the plastic housing 19 if the screw(s) is/are not fastened properly. As a result, the circuit board 14 may be tilted or bent, not only making the connector 14a easily prone to damage and creating a poor contact between the cable P and the circuit board 14, but also affecting the product quality.